451 



turns and retraces its steps over the base as far as the stem, then 

 turns again and continues toward the nest. 



3 132 P.M. I take No. 4 just as it reaches the top disk, coming 

 from the food, and place it on the lower disk near the trail. It starts 

 on the trail toward the nest, crosses to the under side of the disk, 

 then turns and comes again to the upper side, wanders about for a 

 while near the edge, goes to the lower side, back to the upper, then 

 on the trail again to the lower side, follows the trail to the edge of 

 the base, turns and goes back about half an inch, then turns again 

 and continues towards the nest. 



3 150 P.M. I take No. 5 from the edge of the jar, going to the 

 food, and place it on the lower disk near the trail. It crosses the 

 trail three times. The fourth time it comes tO' the trail it follows 

 it to the food, which it reaches at 3 :55. 



4.07 P.M. I take No. 6 just as it reaches the top disk, coming 

 from the food, and place on top of the lower disk near the trail. It 

 follows the trail at once to the nest. 



It will be noticed that the three ants taken as they were coming 

 from the food, Nos. 2, 4, and 6, finally followed the trail to the nest, 

 and that of the three taken as they were coming from the nest, one, 

 No. 3, goes back to the nest, while the other two, Nos. i and 5, con- 

 tinue to follow the trail to the food. This is, of course, insufficient 

 data to base any conclusions whatever upon, so, later on, I isolated 

 two groups of ants on islands in a pan of water for several days, 

 providing one group with plenty of food and keeping the other with- 

 out food. I then transferred them, one at a time, to the new trail 

 which I had caused to be formed in the meantime. The results, how- 

 ever, were not very satisfactory, so I shall not give them in detail. 

 It was impossible for an ant to follow the trail very far without 

 meeting others, and there was often a tendency for the ant placed 

 upon the trail to turn about and follow others which it met, although 

 sometimes it merely stroked antennae with them and went ahead. 



An experiment along this same line consisted in removing one of 

 the disks and replacing it with the lower side uppermost, thus re- 

 versing the direction of the trails on both surfaces. This caused 

 some confusion, but I think no more than was caused by merely re- 

 moving the disk and replacing it in the same position. Although the 

 above experiments are not at all conclusive, yet it seemed to me that 

 the ants merely recognized the trail as such, and could not tell which 

 direction on the trail led to the nest. I did not find in the behavior 

 of these ants any support for Bethe's "Polarized Trail" theory. 

 (Bethe, 1902.) 



